SIGSHR said: In cases like this it's a good idea to either machine rest test the handgun, or if that isn't possible, at least bench rest it, or have it fired by a shooter of known skill.

After any machine rest or bench rest shooting, sight in again using your own hold/stance. Recoil affects your point of impact, and rests often differ from hand-held shooting, as these rests restrain recoil.